Coconut Oil: Friend or Foe?

If you’re like me, you’ve heard the hype around coconut oil and how good it is to incorporate into your diet by adding it into your smoothies and coffee, using it as a cooking oil and even applying topically as a moisturizer. But, not so fast! After diving deeper into the research, it turns out that you can easily get too much coconut oil which can be harmful to your health.

In this post, I’m sharing a thorough article written by Dr. Alvin Berger, where he discusses the benefits of moderate consumption of coconut oil and the evidence that too much is harmful. Dr. Berger recommends consuming no more than 1-3 tablespoons of coconut oil per day, which is still quite a bit as there are 14 grams of fat per tablespoon. The American Heart Association recommends between 44 and 78 grams of fat per day, for someone who consumes 2,000 calories. So if you eat 3 tablespoons of coconut oil, that’s already very close to the daily recommended fat consumption. With coconut oil, or any fat, it adds up quickly!

Coconut Oil – Is it ACTUALLY Good for You?

By Dr. Alvin Berger, MS, Ph. D, Prof.

For the last 50 years or so, it has been generally accepted that saturated fats are bad for our health, specifically heart health. In recent years, there is an increasing realization amongst lay- and technical experts alike, that low fat, high carbohydrate regimens such as the Standard American Diet (SAD) are making us humans more obese and more sick. This in turn, has led to a re-evaluation of the evidence that was used to condemn saturated fats in the first place, and has led some to conclude that saturated fats are not the primary culprit responsible for our ill health after all; some would argue these types of fats are beneficial. Coconut oil is a controversial type of saturated fat that has been either been villainized or glorified with respect to influences on human health. Herein, we will review evidence on both sides of the coconut oil debate to derive some sound recommendations for the reader.

Historical aspects of saturated fat consumption

In early times, the saturated fat on a hunted animal carcass would have been considered to be a valuable source of energy, since fat contains more than twice as many calories on a weight basis (it is more calorically dense) as carbohydrates and proteins. Eating fat to accumulate some adiposity is a valuable survival tool for when calories are less available (say, in the middle of a cold winter when game is less available for hunting).

Likewise, during the World War II years (1940s), when food was scarce, saturated fats such as butter and lard were considered a great energy source; and intriguingly, the glycerin component of fats was also used to make explosives [1].

By the 1980s, saturated fats such as palm and coconut oils accounted for only 4% of the dietary fat consumed. The decline in consumption of saturated fat was driven by increased consumption of soybean oil, which accounted for more than 70% of edible oil consumption (coconutresearchcenter.org).

Driven by endorsements from the American Soybean Association and the consumer crusader Phil Sokolof, we experienced the “tropical oil scare” or tropical grease campaign. During this period, oils such as coconut oil and palm oils were considered to be poisoning America, and they proposed warnings on product labels.

The large increase in saturated fat and coconut oil are driven by low-carb, high fat enthusiast “Paleo” and “Keto” movements.

Historical aspects of coconut oil consumption

Coconut oil is a type of very saturated fat (meaning fewer double bonds, and solid at room temperature). It has been used as a food ingredient and in folk medicine for millennia in tropical regions where coconut trees grow (India, Philippines, Sri Lanka, Malaysia, Polynesia, Indonesia). The oil attracted attention of European traders in the late 19th century, during a time of increased demand for edible oils and soap stock. Europeans established coconut plantations in the Caribbean, SE Asia, and South Pacific from 1890s-1920s and coconut oil was widely used as a cooking oil in Europe and the United States until 1940. During WWII, supply of coconut oil was cutoff to the USA and the soy industry boomed (Coconut Oil Boom, Laura Cassiday, INFORM 27: 6-13, 2016).

There are two main types of coconut oil. Copra is produced by crushing dried coconut kernels to extract the oil, and the oil may then be refined, bleached, and deodorized (RBD).Virgin coconut oil (VCO) is made by pressing shredded wet coconut kernels to squeeze out the oil and coconut milk to form an emulsion. VCO has higher concentrations of tocopherols, tocotrienols (forms of Vitamin E), and healthy polyphenols. Apart from the oil of coconuts, Pacific Islanders used to cook with coconut meat. Now that they cook with coconut oil, they have the worst rates of obesity in the world, although other factors can be involved. In Kerala State in India, they widely consume coconut oil, and have the highest average blood cholesterol level in India (Gupta et al. 2017).

How to evaluate if saturated fats including coconut oil are good or bad for us

When questions are posed such as whether saturated fats are good or bad for our health, this is of course overly simplistic, since the health properties of any oil depend on: a) the amount consumed; b) other non-fatty acid components in the fat (in the case of coconut oil, this would include various fat soluble vitamins); other dietary lipids consumed (for example, saturated fats consumed along side larger amounts of unsaturated fats such as Omega-3s, would affect health differently than each fat alone); c) the processing of the fat (herein, we cover that less processed coconut oil may not be more beneficial); and d) existing health and fitness level of the population studied, amongst many other factors. Also, understanding the many types of clinical data and the statistical approaches employed towards making recommendations is not a trivial matter. There are many types of biases employed in scientific publishing, some overt, some not. An example of publication bias may be to only cite those references that support a particular view point, but to not cite those papers whose authors have opposing views. One would have to be a subject matter expert to detect this type of bias. If an author is a member of the Coconut Oil Board for example, we the reader, should not automatically assume the paper has biases. In most instances, the peer-review process, in which scientists with no conflicts of interests, review the paper before approval, should find and remove any biases during the review process. But, the peer-review process is far from perfect and depends on the expertise of the reviewers, the effort the reviewer is willing to devote, and the quality of the Journal. Animal and pre-clinical data can be important, but sensationalistic journalists often extrapolate from animal data to human conclusion. Although it is wonderful that lay and non-academically trained saturated fat and coconut oil “experts” are spreading their own gospel, they often simply do not have adequate expertise to make the conclusions they spread like wild fire on the internet. Just as I would not like a nutritionist like myself to perform an operation on my knee, why would I want or expect a non-expert to understand all of the above nuances on saturated fat and coconut oil. Ideally, it requires an educated team to understand these nuances, including nutritionists, lipid biochemists, epidemiologists, and biostatisticians.

Governmental agencies’ opinions on saturated fats

Governmental nutritional and dietary agencies are mandatorily staffed by classically trained nutritionists of high academic stature, meaning they have published in high quality journals, in a closely related field. This is good news, but the opinions expressed in their reports will have relied on a great preponderance of evidence, be strongly biased by past publications from the same agency, and such scientists may not be particularly open to more holistic and alternative views. So, ideally, scientists with proper academic credentials, but opposing or partly opposing view, should be selected to serve on committees.

The Dietary Guidelines for Americans Committee (DGAC) are a set of consumption guidelines published by the U.S. Department of Health and Human Services and U.S. Department of Agriculture (USDA), compiled by leading academic nutrition experts reviewing peer-reviewed literature. The 8th Edition, covering 2015-2020, recommends limiting calories from saturated fats (less than 10% of calories from saturated fat), consuming fat free or low fat dairy, eating lean meats. Their conclusions are consistent with those of the American Heart Association (AHA), citing evidence that saturated fats are detrimental to heart health. They rely on the so-called “lipid hypothesis”, stating that there is a direct relationship between the amount of saturated fat and cholesterol in the diet and the incidence of coronary heart disease, as proposed by Ancel Keys in the late 1950’s. Numerous subsequent studies have questioned his data and the conclusions from his “Seven Countries Study” which relied on “fat disappearance” in an epidemiological study. Rather than saturated fat, Key’s famous graph associating fat and saturated intake with heart disease death across seven countries, could also be fitted to sugar consumption and mortality, in these same countries.

Nathan Pritikin was a strong and respected advocate for low fat diets, although he recognized the many flaws in this approach (lack of energy, people could not stay on the diets). His diet called for elimination of sugar and processed foods, but it was the reduction in fat that received the most attention.

The latest guidelines, does recognize that some whole foods such as nuts rich in oils, or some fat-rich whole grains, and some monounsaturated (MUFA) and polyunsaturated (PUFA) oils are healthy, but specifically calls out the tropical oils coconut oil, palm kernel oil (PKO), and palm oil as fats to avoid because of their high fat content. Saturated fats should be limited to 10% of calories per the latest guidelines. Oils are otherwise recommended to be consumed at a level of 27 grams (5 teaspoons), as part of a 2000 calorie diet. Cholesterol is associated with saturated fats in non-plant sources. It is noteworthy that the DGAC now recommends dropping limits on dietary cholesterol, citing no appreciable relationship between dietary cholesterol and serum cholesterol or clinical cardiovascular events in general populations; very early studies in rabbits were actually studying oxidized dietary cholesterol.

In sharp contrast to these DGAC recommendations, groups embracing so called “Keto” and “Paleo” lifestyles (and many other related terms), feel the DGA should be recommending much higher fat intakes, and not demonize saturated fats and tropical fats. They emphasize that decreasing our fat intake and saturated fat intake led to increased added sugar intake, did not decreased caloric intake, and worsened obesity, diabetes, and metabolic syndrome incidence. The Keto and Paleo movements tend to emphasize coconut oil as an example of a very healthy fat.

Evidence coconut oil is unhealthy

Coconut oil is either the panacea that helps everything from bad hair and mental grogginess to obesity and hemorrhoids; or a poison according to Karin Michels, an epidemiologist at the Harvard TH Chan school of public health! Michels scorned the superfood movement and singled out the “coconut oil fad” in particular, calling “coconut oil one of the worst things you can eat that was as good for well being as pure poison”. Michels made her comments in a recent lecture entitled “Coconut oil and other nutritional errors” at the University of Freiburg, where she holds a second academic position as director of the Institute for Prevention and Tumor Epidemiology. The speech, delivered in German (translated here), has been watched nearly a million times on YouTube! Michels based her warning on the high proportion of saturated fat in coconut oil, which is known to raise LDL (bad) cholesterol, and the increased risk of cardiovascular disease associated with saturated fats. Coconut oil has 80-86% saturated fat, twice that found in lard.

Last year, the American Heart Association (AHA), including authors from Harvard University [2] reviewed evidence on coconut oil and other foodstuffs. While three quarters of the US public considered coconut oil to be healthy, the review noted only 37% of nutritionists agreed coconut oil was healthy. The authors attributed the discrepancy in perception to marketing of coconut oil in the popular press. “Because coconut oil increases LDL cholesterol, a cause of cardiovascular disease [and stroke], and has no known off setting favorable effects, we advise against use of coconut oil,” the authors of the review concluded. Other organizations have issued similar warnings. According to the British Nutrition Foundation, “Coconut oil can be included in the diet, but as it is high in saturated fats, it should only be included in small amounts and as part of a healthy balanced diet. There is to date no strong scientific evidence to support health benefits from eating coconut oil.”

In most studies, the focus has been on comparing coconut oil to other saturated fats. In a 2018 study by Maki and colleagues [3], coconut oil consumption was compared to corn oil, an oil rich in polyunsaturated fatty acids (PUFA), and also containing other bioactive, non-fatty acid components (like plant sterols). Foods were prepared with either corn oil or coconut oil (both oils processed to retain vitamins and plant sterols); and effects on lipids, glucose, and inflammation assessed in men (n=12 subjects) and women (n=13) with mean age 45 years, mean body mass index 27.7 kg/m2, fasting LDL cholesterol 150-190 mg/dL, and triglycerides (TGs) ≤375 mg/dL. These cholesterol levels are above optimal levels.The study design was a randomized crossover study (meaning each group received each treatment), with a 3-week washout period between treatments (meaning no diet was consumed during this period). Subjects consumed muffins and rolls providing 4 tablespoons (54 g) per day of corn oil or coconut oil as part of their habitual diets for 4 weeks.

Results: (Changes from Baseline)

Parameter/Group

Corn oil

Coconut oil

Significance between groups

LDL-C

-2.7%

+4.6%

P=0.06

Non-HDL cholesterol

-3.0%

+5.8%

P<0.03

Total-C

-0.5%

+7.1%

P=0.06

HDL cholesterol

+5.4%

+6.5%

Total-C:HDL cholesterol

-4.3%

-3.3%

Triglycerides

-2.1%

+6.0%

hs-CRP, carbohydrate parameters

No differences between groups

The conclusion from this small study in men and women with mildly elevated cholesterol, was that consumption of foods providing 54 g of corn oil/day (along with their habitual diet) produced a more favorable plasma lipid profile than did coconut oil. Specifically, corn oil had more favorable effects on reducing LDL (bad) cholesterol, non-HDL cholesterol (typically LDL+VLDL cholesterol and remnant particles, all are atherogenic particles), and total cholesterol. Both groups raised HDL (good) cholesterol, with no differences between groups. Notably, coconut oil raised trigycerides (not desirable) and corn oil lowered triglycerides (desirable), but due to high variability, no significant differences between groups were noted. It can be argued that LDL particle size (small dense LDL particles being more atherogenic) and more pathologic, modified LDL particles (like oxidized or acetylated LDL particles) were not measured, but in general, even in this statistically underpowered study, the evidence suggests coconut oil to be less beneficial. One can also argue that the study’s results are limited to those with elevated cholesterol at baseline. Indeed, these results should not be readily extrapolated to normocholesterolemic subjects. One last point on this study is that the corn oil used was particularly rich in phytosterols (534 mg/4 tbsp of oil), and this amount is enough to account for part of the observed cholesterol lowering. The crude coconut oil used contained 38.6 mg total sterols/4 tablespoons] along with beneficial tocotrienols, tocopherols, and polyphenols (total phenolic content of 11.8– 29.2 mg gallic acid equivalents/100 g oil). So, it can be argued that the healthiest processed versions of both oils were being compared, at least from a cardiovascular perspective.

In other clinical studies [4], coconut oil also raised LDL cholesterol and total cholesterol relative to corn oil [5], olive oil [6, 7] and high oleic safflower oil [8], similar to results of from Maki and colleagues 2018 study.

Evidence coconut oil is healthy

Despite advice against consuming coconut oil, promotions from health food shops and celebrity endorsements from Gwyneth Paltrow and others, have helped sales of coconut oil surge. In the USA, coconut oil sales peaked in 2015 at $229 MM. Not all “nutrition experts” agree coconut oil is harmful and should be avoided. According to Stephen D. Anton PhD, Associate Professor at the University of Florida’s Institute on Aging, “Coconut oil has been safely used for hundreds of years and has been shown to have a number of health-promoting properties. “Specifically, coconut oil has been shown to increase HDL to LDL ratio (a high HDL/LDL ratio being beneficial for combating heart disease) and to lower overall total cholesterol values.”

Despite the reasonably well designed studies described above showing detrimental effects of saturated fats, some studies have been flawed (such as the aforementioned Keys study); or relied on inappropriate animal models (using animals that metabolize cholesterol differently, or amounts and types of coconut oil not typically consumed by humans).

Those arguing that coconut oil is beneficial, suggest it raises total cholesterol, but also raises HDL (good) cholesterol; and the type of LDL (bad) cholesterol raised, tends to be of the large, buoyant type, which is less strongly associated with cardiovascular disease than small dense, atherogenic LDL particles.

In a meta-analysis (compilation of different clinical studies) of 21 studies published in 2010, the authors concluded “consumption of saturated fat had no observable correlation to heart issues.” It included 347,747 people, followed for an average of 14 years [9]. Meta-analyses attempt to account for all covariables that could affect the outcome of the included studies, and establish rigorous criteria for inclusion and exclusion of each study, but it is exceedingly challenging to combine diverse studies in a systematic, non-biased way, and control for all covariates (variables outside the main ones being measured, that could affect the principal conclusions reached).

In another notable meta-analysis, the Prospective Urban Rural Epidemiology (“PURE”) study, offered a modern view of what a daily diet should look like, with higher fat-to-carb ratios than the long-standing low fat/high carbohydrate status quo. Self-reported dietary data from 135,335 people in 18 countries was collected between January 2003-March 2013, and grouped by amounts of carbohydrate, fat, and protein consumed. After tracking participants’ health over a seven-year period, researchers found those with highest intake of dietary fat (35% of daily calories; low relative to some countries) were 23% less likely to have died than those with the lowest intake of fat (10% of daily calories). Conversely, for carbohydrates, those with the highest intake (77% of daily calories) were 28% more likely to have died than those with lowest intake (46% of daily calories). From these findings the authors’ main conclusion was that “high carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality” [10].“ In this study, coconut oil was not specifically studied.

Opinions of Alvin Berger on coconut oils for nutritional use

To this point, we have provided evidence that coconut oil is healthy and evidence that it is not healthy. As humans do not eat pure coconut oil in a perfectly controlled way, and are in general difficult subjects to work with as compared to experimental lab animals, it is challenging to reach very solid conclusions regarding intake of coconut oil.

Based on the data in hand, I do encourage my customers and patients to limit their intake of coconut oil to 1-3 tablespoons coconut oil per day.

Dr. Alvin Berger

Reasons why I suggest moderation of intake of dietary coconut oil:

Cardiovascular: Early rodent studies testing coconut oil were flawed in that the coconut oil was often hydrogenated producing deleterious trans fatty acids; fed in excessive amounts without essential omega 3s; and oils were fed to rodent species that are poor models for studying cholesterol metabolism (carry most cholesterol in their HDL particles rather than their LDL particles). We can also agree that the early Keys studies was flawed and that subsequent meta analyses and epidemiological studies were flawed or overstated against saturated fats including coconut oil. We cannot however discount that there are numerous properly conducted clinical studies consistently showing that coconut oil raises LDL (bad)- and total cholesterol relative to monounsaturated and polyunsaturated oils. These may not be perfect markers, but they have been clinically validated and associated with negative cardiovascular outcomes for many years.

Coconut oil is not a ketogenic fat: Despite information promoted in the lay press, recent work confirms that coconut oil is not a ketogenic fat [11]. This is not surprising because coconut oil only contains 10-15% of ketogenic C8/10 “true” medium chain fatty acids (as medium chain triglycerides, MCTs), and 50+ percent C12 or lauric acid (similar compositionally to palm kernel oil, PKO).

In early nutritional and lipid/oil/fat textbooks, C12 was considered to be a long chain fatty acid (LCFA). In some more recent text books C12 (lauric acid), perhaps guided by commercial interests and publications, has been considered a MCFA, so that coconut oil can then be claimed to be ketogenic and anti-microbial. Lauric acid is metabolized mostly like other long chain fats in being oxidized or stored in body fat, rather than being preferentially converted to ketone bodies. Some would claim coconut oil is ketogenic because they have a vested commercial interest, and other studies are sponsored by Palm and Coconut oil Boards, who tend to selectively choose literature to match their preferred conclusions.

In the study by Vandenberghe et al., nine healthy adults consumed 2 X 20 mL portions per day (one tablespoon being about 16 grams) of emulsified MCT oils consisting of: coconut oil; C8 MCT oil; C10 MCT oil; C8/10 55:35 MCT oil; or coconut oil diluted 50:50 with C8/10 or C8 oils. Blood was sampled every 30 minutes over 8 hours in a cross-over design. C8 MCT oils were the most ketogenic of the MCTs with highest blood ketones. Other MCT oils tested were less ketogenic than C8. A dose-response could only be shown for C8 MCT, suggesting C8 in MCTs drives ketogenic responses. C10 was not very ketogenic. Coconut oil alone had only a minor effect on increasing ketones, and only after 4-8 hours when no meal was provided (during this same time with food, C8 MCT was 3.4-fold more potent). Coconut oil mixed with C8 MCT oil reduced ketogenicity of C8 MCT oil by 75% as expected. Coconut oil was not more ketogenic after 7-8 hours than the control-some increase in ketones due to fasting observed.

Coconut oil is not antimicrobial in vivo: Despite the plethora of internet claims and some scientific literature, so-called “anti-microbial” properties of lauric acid and lauric acid bound to glycerol, have not been demonstrated in vivo (in living people). When PKO or coconut oil is consumed, the C12 is bound to glycerol to form triglycerides-TAG. The C12 as a free fatty acid (FFA) or monglyceride (MAG) is generated during digestion when acted upon by lipases (enzymes that degrade TAG in our gut), and then rapidly re-esterified to TAG and carried in chylomicron particles in the lymph system, and eventually deposited into our internal fat adipose tissues. So, there are several issues in claiming C12 is anti-microbial. First, any pathogen or microbial killing properties of lauric acid have been published in literature, for the free acid or monoglyceride form, not the digested triglyceride form. Second, the anti-microbial properties of lauric acid as a FFA or MAG were found to occur in test tubes or other experimental ex vivo systems outside the living body.Third, people confuse the well-established food preservative, microbial-killing properties of lauric acid as a FFA or MAG, with the ability to kill organisms in vivo in humans. Fourth, with recognition that many microbes are good for us in the human gut (and on the skin), it is a vast over-simplification to speak of “anti-microbial” properties so broadly. Fifth, assuming there were anti-microbial properties, we need to establish, in vivo, not only that harmful organisms are killed, but that the level of killing has physiological relevance. Last, what dose of lauric acid would be needed to have positive anti-microbial properties in vivo? So called “oil pulling” or swishing coconut oil in the mouth to kill microbes, popular in traditional Indian culture and now the USA, has no proven efficacy beyond anecdotes. Claims made for coconut oil having benefits for the skin are in some cases also flawed, because there is focus on the anti-microbial properties of lauric acid, without recognition that lauric acid in the free form or MAG form would only be generated upon skin lipase action, which is largely of microbial nature.

Coconut oil can have a soapy taste and other quality control issues: Since soap is sodium dodecyl (C12) sulfate (SDS), or sodiumlauroylsulfate, if lauric acid is present as a free fatty acid (free fatty acids do occur in coconut oils), and has opportunity to react with sodium and sulfate, then soaps are formed. In our household, we have had soapy coconut oil in the house, and the taste was quite awful. It is published that coconut oil in contact with water generates rancid coconut oil that is not suitable for oral and cosmetic applications. Coconut oil can also be adulterated, with PKO or RBD coconut oil added to virgin coconut oil to cut costs.

Crude coconut oil may not be healthier than processed coconut oil: Polycyclic aromatic hydrocarbons (PAHs) are formed by combustion and thermal decomposition (pyrolysis) of organic substances in coconut shells. Some PAHs are highly carcinogenic such as benzo-[a]-pyrene and dibenzo-[a,h]-anthracene. It is reported that crude, less refined coconut oils can have higher levels of PAHs and that PAHs are mostly or completely removed during oil refining [12]. Processing of palm oils is also reported to decrease PAHs in most cases.Moreover, in developing countries of South Asia, PAH concentrations are strongly influenced by the monsoonal rainfall system in the region and it has been supported by many studies that higher concentrations were measured during the winter season as compared to summer. Biomass burning (household and brick kilns activities), open burning of solid wastes and industrial and vehicular emissions were categorized as major sources of PAHs in the region [13]. I have heard from reliable sources, that burning of car tires in the vicinity of coconut oil production, also generates PAHs. So, PAHs can become incorporated into coconut oils from a variety of sources. Overall, then the consumer purchasing virgin or less processed coconut oils, must have a deep understanding of the source they are purchasing and ask to see analytical results on PAHs and other contaminants.

Conclusions

Herein, I have provided historical backgrounds on saturated fats and coconut oils, and provided guidance on how the health benefits of coconut oil should ideally be determined. Despite the imperfect clinical data available, in my view, the credible available data suggests coconut oil consumption should be limited to 1-3 tablespoons per day. Coconut oil should not be consumed for its ketogenic and anti-microbial properties, because there is not credible evidence to suggest it has these properties. If coconut oil is to be consumed, there are advantages to consuming a more refined/processed oil over a virgin-, less processed oil; but if the latter is chosen, ask the manufacturer for the levels of contaminants and pollutants in the oil.

About the Author:

Dr. Alvin Berger has 30 years of research experience in nutritional and pharmaceutical sciences, and is an eminent lipid nutritionist and biochemist. He is a world renowned published expert in the field of fatty acids and cellular-, molecular- and whole body metabolism. He is an Adjunct Professor of Nutrition at the University of Minnesota, CEO SCIADONICS/SciaEssentials™, and Co-Founder Life Sense International.

References

1. Walker, T.B. and M.J. Parker, Lessons from the War on Dietary Fat. Journal of the American College of Nutrition, 2014. 33(4): p. 347-351.